After all the different pickup-making techniques I’ve experimented with along this particular journey, I’m back to making cardboard bobbins.

Why, you ask? Well, first of all the bobbin flanges need to be very thin. Like .02”. I was using Garolite and FR4 before, but I was using cylindrical pole pieces; drilling 1/4” holes into the flatwork is relatively easy. The ceramics are bar magnets – cutting nice slots into the Garolite or FR4 by hand is no fun. No fun at all! I figured I’d get those pieces laser-cut ‘cuz it’s pretty cheap. However, there was a monkey wrench in my plan! Most of the stiffer industrial plastics they have available at the hobby-grade laser cutting places are things like Delrin or polypropylene and they are resistant to glues and such. Other plastics they had aren’t chemical resistant. I called around, and none of them seem to want to cut FR4 and stuff like that.

So, cardboard. And that’s fine. It’s easy to glue and the bobbins are really easy to make. I just cut a 3/16” strip of stiff architectural paper, wrap it around a magnet that I use as a form, and tack it on to the pre-cut bobbin. Plus, the pre-cut cardboard flatwork is cheap – like 20¢ each.

The only downside is that it’s not very strong and the bobbins are prone to flaring. I may have to do a slightly looser wind with 44awg instead of 43 – which I think will be OK. I don’t think it’ll change the sound enough so that it will be a deal-breaker. I dunno – I’ll experiment with that.

Bruce showed me these things he’d made to sandwich his bobbins onto his winder. I’ll have to make something similar to keep the bobbins from flaring. I’ll coat the sandwich thingies with wax and leave the wound bobbins in there while I apply the Penetrating Epoxy Sealer. Once that hardens for a day or two, I can take them out. Theoretically, the copper wire and cardboard bobbins will be just one hard happy lump of epoxy-coated goodness.

After that, I gotta make a new master for casting. The old one, pictured below was made for cylindrical magnets. I need to cut one with a slot. Using the limited tools I have at my disposal will make this an interesting project to say the least!

This week was mostly busy work. Most noteworthy, I took a few beginning steps to start a small production run of my NeodymiumSidewinderBass Pickup. I dropped off some drawings of the parts with Bruce over at Johnson’s Extremely Strange Musical Instrument Company. Bruce is going to machine some nice masters that I can use to make molds for my parts. Basically, I decided that I have reached the point where I want to refine the design of my pickup and develop my production model. In the meantime, I’ll call around and get some quotes for getting the blades water-cut out of 430 stainless. I will start off with a few samples and see how they work with the molds. I’m feeling excited about it and I think it will be good to “finished” with my first design. As things progress, I’m sure I’ll be more excited about it.

On another note, I tried to take a few days off and give my brain a rest from pickup making. However, I failed spectacularly and came up with a drawing of a new sidewinder pickup that I think I can make reversible.

Like this:

I managed to epoxy the pickup pieces together last night. It came out OK. Once I clean it up a bit, it’ll be fine.

As far as my pickup assembly, I just took all the loose parts and glued them together. I didn’t get a chance to take many photos photos because it wasn’t exactly and orderly process. The dog ears didn’t fit as well as they did in the dry run, and one of them was slightly askew. I’ll be able to sand it in such a way that it will work, and most of the problem spots will be inside the guitar and won’t be visible anyway.

One thing I’d really like to do is eliminate the process of gluing the blades and coils together. I’m thinking if I put a little groove on those nubs on the sides of my coils, I might be able to make the dog ear serve as a snap-together part and use spacers to set those pieces apart. I don’t have the machining capabilities for something that refined, but it’s something to think about. I have to really fine tune all the parts so that they all fit together and ensure that they are straight and parallel.

Gluing the baseplate to the bottom of the pickup wasn’t bad at all. Everything seemed to survive OK. I could easily make that process easier by making a simple jig to hold the baseplate in place with the rest of the pickup. I attached a photo showing my wire terminals. I have hole behind them where I’m hoping to attach a ground wire. I stuck a piece of copper tape that stretches across the blades.

Overall, I’m happy enough with this as a prototype for my neodymium sidewinder design. However, I’m torn; there’s a lot I would like to do to refine and perfect this design and perhaps make it more of a production piece but I would also like to move on and build a bass and put this pickup in it. In addition, I’m also starting to come up with more pickup designs that I’d like to start working on as well. In conclusion, I’m at a point where I have take a few minutes to relax an do some prioritizing. Refining this design is pretty high on the list, but to a certain degree I’m constrained by what I can execute using the limited tools I have at my disposal. I may have to invest in more tools or tooling to take this one to the next step. In the meantime, now that I have a working prototype in my hands, I can get back on track and start cutting some wood.

I wound the new bobbin with the more closely spaced poles the other night – definitely a better approach than building the bobbin around the neodymium cores. Basically, I glued the blank flanges to the keepers and using the keepers as a drill template, I bored the holes in the blank flanges.

They came out pretty good! I think that drill schedule will work better. It certainly took a less time. Casting and sanding the keeper is still taking a while. I’ll have to work on that. I had a little more trouble with flaring. I think having the magnets in there added more gluing surface. If this magnet-less winding procedure works, I might look into making another plate for the winder that sandwiches the bobbin in there so it won’t flare.

Next, I epoxied the wire terminals to the bobbins.

I used those breakaway header pins. You can’t beat ’em for cheapness or convenience, although I’m still troubled by this joint; when I solder, the housing heats up enough for the wire to loosen. It hardens back up as it cools, but I can see this being problematic. I’m going to look into making some little mount out of stripboard and try using the right-angle pins instead.

First off, let me describe a little bit of my research and development process. At this point, I’ve wound a good number of coils and assembled a good number of prototypes. On my desk, I have about 20 different coils of varying size, shapes and materials. I’ll plop one pickup into the tester bass, rock out on it for a few days, make a few adjustments and if I like what I’m hearing, I’ll keep going with it. Sometimes, I’ll spend a few weeks with one idea, and decide for whatever reason it’s not what I’m looking for. But then, after trying a few other ideas, I may (or may not) come back to the previous idea.

In any case, for a number of reasons, I’m back on the neodymium sidewinder. Initially, and in closing a lot of it has to do with the form as well as the tone. Because the neodymium are so small and insanely strong, I can build a smaller pickup with lots of output. I found a shape I liked, and ultimately discovered that the geometry of the coil is one of the largest contributors to both overall output and tonal characteristics. From there, I was able to make variation after variation using different wire gauges and turn counts. At this point, I’m down to maybe 3-4 different versions of the same pickup that I like and eventually I will select the “final” pickup from this pool – or perhaps I’ll even make a slight variation based on one of these pickup. Overall, I like the sound – I have enough bass, mids and high end. The neos render an aggressive sound without being too stiff like the ceramic-based coils. I’d say that they have a lot more warmth than ceramic, but more attack than say, A5.

After attempting a few different styles of cast shells, I started kicking this idea around:

Basically, the coils will be cast individually and then sandwiched between the steel blade poles. The neos are so strong that it takes a considerable amount of effort to pry the pieces apart, so structurally, I think this will be pretty solid despite being held together primarily by sheer magnetism. The dog ears will then be epoxied on to the sides to really hold them together. The base plate (not pictured) will be also epoxied to the bottom, also adding extra security. I’ll wind and cast the coils without the magnets. I can then drill out the core and insert the magnets afterward.

This form also provides for and solves many esthetic quandaries I’ve been having throughout this project; first and foremost, there’s lots of cool-looking exposed metal. I also changed the spacing of the poles – previously, I had them two to a string like a Jazz Bass pickup. I moved them closer together because A) I’ll save about 1/4″ of width, and B) once the magnets are in touch with those steel poles, I don’t think that the magnet spacing will make much difference in the final outcome.

I made some originals for this over the weekend and hope to make molds later this week.

Lastly, on another bit of news, I started a little blog about my pickup making about week or two ago. I’ll be posting my big forum posts there as well as some additional stuff, like Instagram images, etc. It started as a convenient way for me to keep track of my notes, and it went from there. The look for now is completely stripped to just pictures and words – no layout. Part of my day job is in fact, building WordPress sites. I just wanted something to post pictures and a few words and focus on that and nothing else. I may build the theme out later. BTW, the site automatically ads my Instagram shots as individual posts, so those get updates a couple times a week.

A polyurethane keeper I pulled from the mold. I still need to cut the flashing and sand the edge flat. Those little neodymium magnets are very strong and unruly. I designed this little cast keeper bar to keep them in place. #funktronicpickups #winding #handwoundpickups #basspickups #madscientist #neodymiummagnets #guitarpickups